The probe was sparked when the hospital’s chairman Terry Currie asked experts at auditors KPMG to look into an “anonymous allegation”.

It was revealed in 2013 that payments totalling £50,000 were given to board members.

The payments were dubbed “danger money” for working in a high-security environment – despite the fact they did not come into contact with patients.

Chief executive Andreana Adamson left her role after an outcry over the payments.

Her resignation also coincided with an internal probe into bullying at the hospital.

A report later found no evidence of fraud or serious misconduct, but criticised bosses’ handling of the issue.

It also found bullying was a “running theme” during the probe.

About 700 people work at the hospital, caring for up to 140 patients.

The 14 bullying cases were revealed yesterday.

In a statement, the hospital said: “The State Hospital’s Zero Tolerance to Bullying and Harassment campaign has a clear objective of telling people that it is safe to complain.

“Any issues raised are addressed promptly and professionally. Dignity at Work remains a high priority for the board and we aspire to meet the aims of the staff governance standard whereby everyone in the State Hospital is always treated with dignity and respect."

Scotland’s Minister for Mental Health Jamie Hepburn said: “I am very clear that we will not tolerate bullying of any kind in our NHS.

“It is not good for our hardworking NHS staff - particularly in an already challenging environment like the State Hospital - and it is not good for patients.

“It is also vitally important that all NHS workers feel that they can raise any concerns they may have safely and confidentially, and be reassured that health boards will listen.”